C-Band GaN-HEMT Power Amplifier with Over 300-W Output Power and Over 50-% Efficiency

In this paper, we report a C-band power amplifier with over 300-W output power using 0.8-mum GaN-HEMTs. We used two-chip configuration and the three-stage impedance transformer to extend the bandwidth. The input and output lines adjacent to each chip are divided by four to suppress the non-uniform heat distribution in a chip at high frequencies. We confirmed that the uniform heat distribution in each chip under RF operation at 4.8 GHz. As a result, we obtained over 320-W output power and 57 % drain efficiency at 4.8 GHz. This is the highest output power of the one-package power amplifiers at C-band. We also obtained over 250-W output power and over 44-% drain efficiency between 4.7 GHz and 5.3 GHz.